﻿ 
using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Linq;
using System.Text;
using System.Drawing;
using System.Drawing.Printing;
using System.Windows.Forms;
using NPOI.XSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.HSSF.UserModel;

namespace Utils.Common
{
    public class ExcelHelper  
    {

        public static DataTable GetDataTable(string filepath, int startRow = 0)
        {
            DataTable dt = new DataTable();
            if (filepath.Last() == 's')
            {
                dt = ExcelHelper.ExcelToTableForXLS(filepath, startRow);
            }
            else
            {
                dt = ExcelHelper.ExcelToTableForXLSX(filepath, startRow);
            }
            return dt;
        }

        #region Excel2007
        /// <summary>
        /// 将Excel文件中的数据读出到DataTable中(xlsx)
        /// </summary>
        /// <param name="file"></param>
        /// <returns></returns>
        public static DataTable ExcelToTableForXLSX(string file, int startRow = 0)
        {
            DataTable dt = new DataTable();
            using (FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Read))
            {
                XSSFWorkbook xssfworkbook = new XSSFWorkbook(fs);
                ISheet sheet = xssfworkbook.GetSheetAt(0);

                //表头
                IRow header = sheet.GetRow(startRow);
                List<int> columns = new List<int>();
                for (int i = 0; i < header.LastCellNum; i++)
                {
                    object obj = GetValueTypeForXLSX(header.GetCell(i) as XSSFCell);
                    if (obj == null || obj.ToString() == string.Empty)
                    {
                        dt.Columns.Add(new DataColumn("Columns" + i.ToString()));

                    }
                    else
                        dt.Columns.Add(new DataColumn(obj.ToString()));
                    columns.Add(i);
                }
                //数据
                for (int i = startRow + 1; i <= sheet.LastRowNum; i++)
                {
                    DataRow dr = dt.NewRow();
                    bool hasValue = false;
                    foreach (int j in columns)
                    {
                        if (sheet.GetRow(i) != null)
                        {
                            dr[j] = GetValueTypeForXLSX(sheet.GetRow(i).GetCell(j) as XSSFCell);
                            if (dr[j] != null && dr[j].ToString() != string.Empty)
                            {
                                hasValue = true;
                            }
                        }
                    }
                    if (hasValue)
                    {
                        dt.Rows.Add(dr);
                    }
                }
            }
            return dt;
        }

        /// <summary>
        /// 将DataTable数据导出到Excel文件中(xlsx)
        /// </summary>
        /// <param name="dt"></param>
        /// <param name="file"></param>
        public static void TableToExcelForXLSX(DataTable dt, string file)
        {
            XSSFWorkbook xssfworkbook = new XSSFWorkbook();
            ISheet sheet = xssfworkbook.CreateSheet("Test");

            //表头
            IRow row = sheet.CreateRow(0);
            for (int i = 0; i < dt.Columns.Count; i++)
            {
                ICell cell = row.CreateCell(i);
                cell.SetCellValue(dt.Columns[i].ColumnName);
            }

            //数据
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                IRow row1 = sheet.CreateRow(i + 1);
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    ICell cell = row1.CreateCell(j);
                    cell.SetCellValue(dt.Rows[i][j].ToString());
                }
            }

            //转为字节数组
            MemoryStream stream = new MemoryStream();
            xssfworkbook.Write(stream);
            var buf = stream.ToArray();

            //保存为Excel文件
            using (FileStream fs = new FileStream(file, FileMode.Create, FileAccess.Write))
            {
                fs.Write(buf, 0, buf.Length);
                fs.Flush();
            }
        }


        /// <summary>
        /// 获取单元格类型(xlsx)
        /// </summary>
        /// <param name="cell"></param>
        /// <returns></returns>
        private static object GetValueTypeForXLSX(XSSFCell cell)
        {
            if (cell == null)
                return null;
            switch (cell.CellType)
            {
                case CellType.Blank: //BLANK:
                    return null;
                case CellType.Boolean: //BOOLEAN:
                    return cell.BooleanCellValue;
                case CellType.Numeric: //NUMERIC:
                    return cell.NumericCellValue;
                case CellType.String: //STRING:
                    return cell.StringCellValue;
                case CellType.Error: //ERROR:
                    return cell.ErrorCellValue;
                case CellType.Formula: //FORMULA:
                    if (cell.CachedFormulaResultType == CellType.Numeric)
                    {
                        return cell.NumericCellValue;
                    }
                    else
                    {
                        return cell.StringCellValue;
                    }
                default:
                    return "=" + cell.CellFormula;
            }
        }
        #endregion


        #region Excel2003
        public static DataTable ExcelToTableForXLS(string file, int startRow = 0)
        {
            DataTable dt = new DataTable();
            HSSFWorkbook hssfworkbook;
            using (FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Read))
            {
                hssfworkbook = new HSSFWorkbook(fs);
                fs.Close();
            }
            ISheet sheet = hssfworkbook.GetSheetAt(0);



            //表头
            IRow header = sheet.GetRow(startRow);
            List<int> columns = new List<int>();
            for (int i = 0; i < header.LastCellNum; i++)
            {
                object obj = GetValueTypeForXLS(header.GetCell(i) as HSSFCell);
                if (obj == null || obj.ToString() == string.Empty)
                {
                    dt.Columns.Add(new DataColumn("Columns" + i.ToString()));
                }
                else
                    dt.Columns.Add(new DataColumn(obj.ToString()));
                columns.Add(i);
            }
            //数据
            for (int i = startRow + 1; i <= sheet.LastRowNum; i++)
            {
                DataRow dr = dt.NewRow();
                bool hasValue = false;
                foreach (int j in columns)
                {
                    if (sheet.GetRow(i) != null)
                    {
                        dr[j] = GetValueTypeForXLS(sheet.GetRow(i).GetCell(j) as HSSFCell);
                        if (dr[j] != null && dr[j].ToString() != string.Empty)
                        {
                            hasValue = true;
                        }
                    }
                }
                if (hasValue)
                {
                    dt.Rows.Add(dr);
                }
            }

            return dt;

        }
        private static object GetValueTypeForXLS(HSSFCell cell)
        {
            if (cell == null)
                return null;
            switch (cell.CellType)
            {
                case CellType.Blank: //BLANK:
                    return null;
                case CellType.Boolean: //BOOLEAN:
                    return cell.BooleanCellValue;
                case CellType.Numeric: //NUMERIC:
                    return cell.NumericCellValue;
                case CellType.String: //STRING:
                    return cell.StringCellValue;
                case CellType.Error: //ERROR:
                    return cell.ErrorCellValue;
                case CellType.Formula: //FORMULA:
                    if (cell.CachedFormulaResultType == CellType.Numeric)
                    {
                        return cell.NumericCellValue;
                    }
                    else
                    {
                        return cell.StringCellValue;
                    }
                default:
                    return "=" + cell.CellFormula;
            }
        }


        #endregion






 


        

    }
 
}

